Without deets on what, or how it failed we can only guess.
Mine is that you went OTB, had a yard sale, the bike tasted some solo air..
And the shifter, barrel adjuster snapped off from the shifter body.
(with Flyin_W, as a moniker, and an unintentional OTB acrobat - I've broken a couple of them exactly this way.)
Don't H8, or buy plastic bike parts.
... tapas

no falls, crashes, OTB or anything like.
Riding on the road to the trail. Went to change gear, the lever free swung without engaging.
Upon taking apart the underneath part of the shifter, there is supposed to be a small piece of metal that sticks up and engages the upper side ratchet of the shifter, this sheared off (twice for me on 2 different shifters and same for the one received the same day at the LBS). You could not break this by crashing, it is caused by metal resembling mercury.